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1 tháng 7 2018

\(\frac{7}{13}.\frac{5}{19}+\frac{7}{19}.\frac{8}{13}-3\frac{7}{19}\)

\(=\frac{7}{19}.\frac{5}{13}+\frac{7}{19}.\frac{8}{13}-3-\frac{7}{19}\)

\(=\frac{7}{19}\left(\frac{5}{13}+\frac{8}{13}\right)-3-\frac{7}{19}\)

\(=\frac{7}{19}-3-\frac{7}{19}\)

\(=-3\)

1 tháng 7 2018

\(\frac{7}{13}.\frac{5}{19}+\frac{7}{19}.\frac{8}{13}-3\frac{7}{19}\)  

=\(\frac{7}{19}.\frac{5}{13}+\frac{7}{19}.\frac{8}{13}-3-\frac{7}{19}\)

\(\frac{7}{19}.\left(\frac{5}{13}+\frac{8}{13}\right)-3-\frac{7}{19}\)

\(\frac{7}{19}-3-\frac{7}{19}\) =  \(-3\)

13 tháng 3 2016

\(\frac{7}{13}.\frac{5}{19}+\frac{7}{19}.\frac{8}{13}-\frac{37}{19}=\frac{1}{19}\left(\frac{5.7}{13}+\frac{7.8}{13}-37\right)=\frac{1}{19}\left(\frac{91}{13}-37\right)=\frac{1}{19}.\left(-30\right)=-\frac{30}{19}\)

13 tháng 3 2016

\(=\frac{4x3x7x\left(-20\right)x\left(-11\right)}{7x5x4x12}=\frac{4x3x7x5x4x11}{7x5x4x3x4}=11\)

3 tháng 3

\(\frac37+\frac{5}{13}+\frac{4}{13}\)

=\(\frac37+\left(\frac{5}{13}+\frac{4}{13}\right)\)

=\(\frac37+\frac{9}{13}\)

=\(\frac{39}{91}+\frac{63}{91}\)

=\(\frac{102}{91}\)

3 tháng 3

\(\left(\frac38+\frac{-3}{4}+\frac{7}{12}\right):\frac56+\frac12\)

=\(\left(\frac{9}{24}+\frac{-18}{24}+\frac{7}{24}\right)\times\frac65+\frac12\)

=\(\frac{5}{24}\times\frac65+\frac12\)

=\(\frac14+\frac12\)

=\(\frac14+\frac24\)

=\(\frac34\)

2 tháng 6 2017

\(a.\) \(\frac{4}{15}.\frac{7}{9}+\frac{4}{15}.\frac{2}{9}\)

\(=\frac{4}{15}\left(\frac{7}{9}+\frac{2}{9}\right)\)

\(=\frac{4}{15}.\frac{9}{9}\)

\(=\frac{4}{15}.1\)

\(=\frac{4}{15}\)

\(b.\) \(\frac{13}{19}.\frac{23}{11}-\frac{13}{19}.\frac{8}{11}-\frac{13}{19}.\frac{4}{11}\)

\(=\frac{13}{19}\left(\frac{23}{11}-\frac{8}{11}-\frac{4}{11}\right)\)

\(=\frac{13}{19}.\frac{11}{11}\)

\(=\frac{13}{19}.1\)

\(=\frac{13}{19}\)

2 tháng 6 2017

a)4/15 x(7/9+2/9)=4/15x1=4/15

b)13/19x(23/11-8/11-4/11)13/19x1=13/19

ta có;

b=8/3.2/5.3/8.10.19/92

b=16/15.3/8.10.19/92

b=2/5.10.19/92

b=4.19/92

b=19/23

c=-5/7.2/7+-5/7 . 9/14+1/5/7

c=-10/49+(-45)/98+1/5/5

c=131/98

12 tháng 4 2017

ai tk mình đi mk bị âm

3 tháng 5 2019

Giúp Mik ik mai nộp oy

3 tháng 3

\(\frac27\times5\frac14-\frac27\times3\frac14\)

=\(\frac27\times\left(5\frac14-3\frac14\right)\)

=\(\frac27\times\left(\left(5-3\right)+\left(\frac14-\frac15\right)\right)\)

=\(\frac27\times\left(2+0\right)\)

=\(\frac27\times2\)

=\(\frac47\)

j) \(\frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10.\frac{19}{92}=\left(\frac{8}{3}.\frac{3}{8}\right).\left(\frac{2}{5}.10\right).\frac{19}{92}=1.4.\frac{19}{92}\)

\(=\frac{19}{23}\)

k)\(\frac{-5}{7}.\frac{2}{11}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}=\left(\frac{2}{11}.\frac{19}{12}\right).\left(\frac{-13}{17}.\frac{17}{13}\right).\frac{-5}{7}\)

\(=\frac{-19}{66}.\frac{-5}{7}=\frac{95}{462}\)

l)\(\frac{12}{19}.\frac{7}{15}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}=\left(\frac{12}{19}.\frac{19}{12}\right).\left(\frac{-13}{17}.\frac{17}{13}\right).\frac{7}{15}\)

\(=\frac{-7}{15}\)

cậu tham khảo trên này ạ, nếu đúng cho mk 1 t.i.c.k ạ, thank nhiều

31 tháng 8 2020

b) \(\frac{12}{19}.\frac{7}{15}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}=\frac{12}{19}.\frac{19}{12}.\frac{-13}{17}.\frac{17}{13}.\frac{7}{15}=1.\left(-1\right).\frac{7}{15}=\frac{-7}{15}\)

31 tháng 8 2020

\(-\frac{5}{7}.\frac{2}{11}+-\frac{5}{7}.\frac{9}{14}+\frac{12}{7}=-\frac{5}{7}.\left(\frac{2}{11}+\frac{9}{14}\right)+\frac{12}{7}=-\frac{5}{7}.\frac{127}{154}+\frac{12}{7}=-\frac{635}{1078}+\frac{12}{7}=\frac{1213}{1078}\)

\(\frac{12}{19}.\frac{7}{15}.-\frac{13}{17}.\frac{19}{12}.\frac{17}{13}=\left(\frac{12}{19}.\frac{19}{12}\right).\left(-\frac{13}{17}.\frac{17}{13}\right).\frac{7}{15}=1.-1.\frac{7}{15}=-\frac{7}{15}\)